#! /bin/sh
## zloop - loop through compressed/gzipped file(s), running command on each
## Usage: zloop 'command to run' file.(Z|gz) [files.(Z|gz)...]

myname="`basename $0`"
zcat=/usr/local/bin/gzcat	# GNU zcat THAT HANDLES BOTH compress AND gzip

case $# in
0|1) echo "Usage: $myname 'command to run' file.Z [files.Z...]" 1>&2
	exit 1
	;;
esac

# AT LEAST, CATCH PROBLEM WHERE MULTI-WORD COMMAND ISN'T QUOTED:
case "$2" in
*.Z|*.gz) ;;
*) echo "Usage: $myname 'command to run' file.(Z|gz) [files.(Z|gz)...]
	('$2' doesn't look like a compressed file.Z or gzipped file.gz)." 1>&2
	exit 1
	;;
esac

cmd="$1"; shift

for file
do
	# DO IN ONE echo BECAUSE echo SUB-PROCESS IS ALREADY WASTE OF TIME:
	echo "
==== $myname: zcat $file | $cmd ====" 1>&2
	eval $zcat $file \| $cmd
	status=$?
	case "$status" in
	0) ;;
	*)	echo "$myname: note: that command returned $status (non-zero) status:
		'$zcat $file | $cmd'" 1>&2
		;;
	esac
done